This invention relates generally to the manufacture of dendritic particles, and the use thereof and, more particularly, to the manufacture of acicular branched metal dendritic particles, and the use thereof.
Traditionally, springs and pins have been used to provide connection between electrical elements such as pads. However, as densities increase, these types of connections are often not sufficient. With higher densities, compressible pad-on-pad connections are often used. While in many cases these types of connectors are very useful, nevertheless in some instances they are not completely reliable. For example, when the pads or other contacts have films, such as oxide films or the like or dust particles, or any other surface contaminants, or connectors that use a conductive elastomer/plastic material, such conductive elastomers may not provide the necessary contact with the pads. This is because the conductive elastomer is normally provided with relatively soft metal conducting particles, such as silver. When the particles encounter the film, they may not penetrate the film, but rather deform, leaving the film as an insulating barrier between the conductive pad and the conductive particles. This sometimes results in less than the quality connection required.
According to the present invention, a technique for making acicular, branched, conductive dendrites, and a technique for using the dendrites to form a conductive compressible pad-on-pad connector are provided. To form the dendrites, a substrate is provided on which dendrites are grown, preferably on a metal film. The dendrites are then removed from the substrate, preferably by etching metal from the substrate. The so formed dendrites are incorporated into a compressible dielectric material, which then forms a compressible pad-on-pad connector between two conducting elements, such as connector pads on electrical devices, e.g. an I/C chip mounted on a substrate, such as a chip carrier.